The 8-bit card talks to the CPU 8 bits or 1 character at a time. This card is also known as an ISA card and has one tab that plugs into the expansion slot. These cards are generally used in older PCs, 8088-386s.

The 16-bit card talks to the CPU twice as fast as the 8-bit card. It talks to the CPU 16 bits or 2 characters at a time. This card is also known as an ISA card and has two tabs that plug into the expansion slot. These cards are used in 286 through Pentium PCs.